Air conditioning system



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V AIR CONDITIONING SYSTEM Filed Jan. 12, l 939 3 SheAetS-Sheet 2 .I lllll e mi Dec. 23, 1941. F. L. MURPHY AIR CONDITIONING SYSTEM Filed Jan. l2, 1939 3 SheetS-SheekI 5 Patented Dec. 23, 194i UNITED STATES PATENT CFFICE l 2,266,986 l I f AIR CONDITIONING SYSTEM Frank L. Murphy, Chicago, Ill., assignor to'Pullman-Standard Car Manufacturing Company, Chicago, Ill., a corporation lof Delaware Application January 12, 1939, Serial No. 250,529

y claims The present invention relates to' an air conditioning system for a rail car and one of its principal objects is to provide a system which produces an even temperature throughout the passenger space. Other objects and advantages will become apparent as the disclosure proceeds and the description is read in conjunction with theaccompanying drawings, in which Fig. 1 is a diagrammatic view of the car interior showing the relative positions of the indi` air distribution system .plete controls for the'heating and cooling systems.

throughout the car interior,` and this is accomplished by employing two or more complete air conditioning and circulating systems, .each controlled separately by separate thermostatic controls. y

GENERAL ORnANIzA'rIoN The invention isi shown applied to a railway car generally indicated at I8, having an under- 1 frame I I (see Fig. 3), a pair of side frames I2 and I3, and a roof I4. As shown, a vestibule I5 is provided at one end of the car having the usual vestibule doors I8, and at the other end of the car is positioned a dummy end generally indicated at I5.

For the purpose 'of disclosure, the car body interior is shown VVprovided with a plurality of roomette sections generally indicated at I1, position on both sides of an aisle I8 lwhich extends throughout the length of the car and is positioned substantially along the car center line.

Each roomette section is provided with suitable accommodations, some of which are shown, and

For the purpose of disclosure only, a particular embodiment of the present invention has been selected, but obviouslyV many changes may be made without departing from thescope of the invention.

The requirement for air conditioning in a rail- 'way car is not uniform throughout the entire car body interior. example of this situation,

let it be assumed that a car is operating in cold weather at a time of year when there is considerable warmth in the suns rays. With the sun shining. on one side of the car only, the eiect` of the suns rays will be felt only on that side of the car, so that the demand for car heating vwill be less on the sunny side of the car than on the shady side. If the air conditioning system for the car is controlled by a single thermostatI situatedfor example, on the sunny side, the conditioning system will operate in response to temperature conditions on the sunny or warm side of the car, so that, unless the thermostat is set to a higher degree than would be required for maximum comfort on the sunny side, the occupants in 'space situated on the shady side of the car will suier. Likewise, if the thermostat is situated on the shady side, the passengers occupying the space on the sunny side will be uncomfortably warm.

The same situation will be present when the car is operating in warmweather and the cooling system is functioning; one side of the car is going to be either too warm or too cool. There are factors other than the sun to be considered, as, for example, the wind, but the problem is the same whatever may be the cause.

The present invention is intended to provide a means 4for uniformly conditioning the air include a hopper I9, an upholstered seat 20 positioned over the hoppr, and toilet facilities, in-

cluding a wash basin 2l, a medicine cabinet 22, a wardrobe 23, and other furnishings, including the bed (not shown). A baggage rack 24 may be provided for each room, and a door'25 permits access into the room from the aisle I8. Windows 26 are spaced along the car sides so as to providev at leastone window for each roomette section.

Am CoNnI'rroNiNc SYSTEM The air conditioning system forming the mechanical refrigeration, which includes the usual -compressor l, condenser 8,'and a receiver 9,

mounted underneath the car in the usual manner, a pair of expansion valves (not shown), evaporators 42 and 43, positioned in the conditioned air duct, and suitable piping generally indicated att. The compressorl may be driven from the Acar axle, as generally indicated at 53, and for standby service from an alternating current motor 54. The heating is supplied by steam heating coils drawing steam from the usual train line. i t

Air distribution Extending throughout substantially the entire length of the car are a pair of conditioned air of exhaust air ducts 29 and yJill,v positioned above the conditioned air ducts, 'as shown in Fig. 3.

ducts 21 and 28, mounted side by side, and a pair Separate blower fans 3l and 3|' circulate air through the conditioned air ducts 21 and 28 respectively, and these fans draw their air from a plenum chamber 32 which is supplied with vrecirculated air drawn from the car interior through a recirculated air intake 33 and fresh air which is drawn in from the car vestibule through a fresh air intake 34. A damper arrangement, generally indicated at 35, regulates the proportion of recirculated and fresh air brought into the system. The conditioned air duct 21 discharges into the roomette sections positioned along car side I2 while the air duct 28 ldischarges into sections positioned along car side I3. This conditioned air enters each roomette section I1 through a grill 36, and the greater portion of this air is drawn through an opening 31, positioned in the door of each roomette section adjacent to the floor, and is then passed through the aisle I8 back into the plenum chamber 32 through recirculated air intake 33.

A small portion of air is exhausted from each of the roomette sections I1 through an exhaust outlet 38 and duct 39 into the exhaust air ducts 29 or 30, the ducts being arranged to draw from opposite sides of the car. An exhaust fan 40 is positioned at the end of the exhaust air ducts 29 and 30 and discharges from the car body through duct 4I.

The'air circulation throughout the car body is as follows: The blower fans 3l and 3|' draw air from the plenum chamber 32 and pass this air through the ducts 21 and 28 and into the roomette sections I1 positioned on opposite sides of the car. The greater portion of this air is then passed through the openings 31 positioned in the doors 25 and is then returned through the aisle I8 to the plenum chamber 32 through the inlet 33. Occupants of roomette sections are permitted to smoke while in their sections, and consequently there isan accumulation of a large amount -of smoke which cannot be properly taken care of by the air conditioning system if drawn back into the plenum chamber 32 and Vrecirculated. Consequently, a portion of this smoke, together with other gases and a small percentage of vitiated air, is exhausted from each roomthrough the outlet 38 into the ducts 29 and 30, and hence it isdischarged from the car by means of exhaust fan 40.

The temperature of the air passing through the conditioned air ducts 21 and 28 is regulated by cooling coils 42 and 43, one being positioned in each of the ducts 21 and 28, and heating coils 44 and 45 positioned in the conditioned air ducts 21 and 28 respectively.`

The cooling coils 42 and 43 in the present case are evapcrators being supplied with refrigeration from a compressor 1 (Fig. 4) which may be mounted underneath the car in the usual manner.

The.operation of the over-head heating coils is controlled byseparate thermostats 45 and 41 positioned in the conditioned air ducts 21 and 28 respectively, while the operation of the cooling coils 42 and 43 is controlled by thermostats 48 and 49 positioned in the `exhaust air ducts 29 and 30 respectively.

Floor heating coils 45I! are positioned in each section and their operation is controlled by thermostats I and 52 positioned in the exhaust air ducts 29 and 30 respectively and controlling the operation of the coils on the opposite sides of the car independently of each other.

CoNraox. SYSTEM Circuit in general The control circuit includes generally a source of current, which is shown as a battery but may be a car generator or any other suitable source, a blower fan switch 56 operating a circuit to the blower fan motor 51, and a seasonal selector switch generally indicated at 58 generally positioned on the electric control panels at one end of the car. This selector switch places diierent parts of the control system in operation and is manipulated by a member of the train crew.

In addition to these elements, the control circuit also includes an overhead heat relay 59,

which responds to the action of the overhead heat thermostat 45 to control the operation of heating coil 44, and a second overhead heat relay 58 which controls thevoperation of the heating coil 45 in response to thermostat 41. The iioor heating coils, indicated at 50 in Fig. 3, are controlled by relays 8i and 52 which function in response to the thermostats 5I and 52 respectively. Floor heat relay 8| controls the operation of the floor coils situated adjacent to car side I2, and relay 62 controls the operation of the heatingl coils positioned adjacent to car side I3. A

The operation of the cooling system is controlled by. a pair oi cooling pilot relays 62 and 53 which control the operation of evaporators 42 and 43 respectively through solenoid valves" 54 and 55 respectively.'

For standby service, vthe alternating current motor 54 drives the compressor' 1 to produce refrigeration and current for running this motor is obtained from an outside source which is plugged in at the receptacle indicated at 86. An A. C. motor contacter relay 81 controls the operation of the A. C. circuit.

In addition to these various controls, the present system also lincludes a heat protection relay 68 which functions to prevent freezing up of the vwater pipes, etc., in a car, in the event that the car is standing in the yards. irrespective of the setting of the seasonal selector switch 58 and at a time when the blower fan switch 56 is turned oif. This heat protection relay operates inl response to a heat protection thermostat 59 an controls the floor heat.

Operation of the control system To place the system in operation, the blower fan switchl 58 is first closed to the dotted line position" indicated at 18, thereby placing the blower fans 3| and.8I in operation. The speed of the fans may be varied by selectively changing the amount of resistance 'in the fan motor eld 1I by means of a rheostat 12 and by changing the resistance in the armature circuit of the blower fan motor 51 by means of a second rheo.- stat 13'. When the blower fan switch 56 is closed, the fan is placed in operation and air is circulating through the ducts 21 and 28. The seasonal selector switch 58 is then turned to the position for cooling or heating, depending upon the season of the year in which the car is operating or upon outside temperature conditions.

Car operating in cold weather As shown in Fig.`4, certain of the contacts in the seasonal selector switch lead to the heat control circuits, while other contacts lead to the.

control circuits for the cooling system.

Assume for the present that the car is operating in cold weather so that the seasonal selectorv switch is positioned for cold weather operation, as, for example, in the position indicated in dotted lines at 14. When the blower fanswitch 56.

is closed to the dotted line position, the current will flow from the positive terminal +R through the fan switch, conductors 15, 16, and 11, contact plate,18, seasonal selector switch blade 14, contact plate 19, conductors 80 and 8|, then through the overhead heat relays 6l) and 59, and then back to the negative terminal -R through conductor 82. Thus the overhead heat relays 59 and 69 are being energized so as to place the relay switches 59' and 69' in the dotted line position so as to complete the circuit to the overhead heat magnetic valves to maintain them in the on position.

The current also ows from the positive terminal +B through conductors 83, 84, and 85, contact plate 86, through seasonal selector switch blade 14, to contact plate 81, conductors 88 and 89, then through the floor heat relays 62 and 6|, and then back to the negative terminal -B through conductors 90 and 9|. Thus the oor heat relays 6| and 62 are being energized to hold the switches 6|' and 62' in the dotted line position so as to maintain the floor heat magnetic valves 84 and 85 in the on position.

If any one' or more of the thermostats 46, 41, 5|, and 52 demand heating, the mercury in the thermostat or thermostats will be in a position to complete the circuit through the thermostat, thereby causing the current to by-pass the corresponding heat relay so as to deenergze the relay and move the corresponding relay switch to its solid line position, thereby turning off the corresponding heat magnetic valve.

Provision is made for varying the temperature of operation of the overhead heat thermostats 46 and 41 and the floor heating thermostats 5| and 52 by providing suitable heater elements 91 and 98 around the overhead and oor heating thermostats respectively. To add varying amounts of heat to the mercury in the thermostats, a bank of resistors, generally indicated at 99, made up of resistor elements of varying delso In each of the iloor heat control circuits is a ballast resistor 93, whose function is to prevent ow of" current passing from the seasonal selector switch through the oor heat thermostat heater elements 98. When the circuit is completed through the dotted line position of each of the :door heat relay switches 6|' and 62', there is a flow of current through the ballast resistor 93, which supplements the normal ow of current through the floor heat thermostat heater elements 5I and 52, thereby greatly increasing the speed of operation of the thermostats to make them much more sensitive in their response to the temperature conditions'of the car interior. A l

There is a corresponding ballast resistor ||0 for each of the overhead heat thermostats, and its function is to increase the sensitivity of the overhead heat thermostats.

Car operating im. warm weather .63 are cle-energized, closing the circuits across the pilot relay switches 62' and 63 respectively, opening the solenoid valves 64 and 65 to complete the refrigeration cycle from the compressor 1.

Refrigeration is now being produced and the blower fan 3| is delivering cool airinto bbth sides of the car. When the car interior'is cooled suiiiciently on one or both sides' of .the aisleyeither or both of the cooling thermostatsA 48 and149 cause the corresponding cooling pilot relays 62 and 63 to become de-energized, thereby opening gre'es of ohms for each resistor element, is placed in the heater circuit for each of the overhead heat thermostats 46 and 41 so as to permit varying the current ilow through the heater elements.

The position of the seasonal selector switchA 58 will determine the amountof resistance in the thermostat heating element circuits. A second position of the seasonal selector switch is indicated at 92.

Similarly, the current flowing through the heating elements for the floor heat thermostats 5! and 52 may be varied.

either or both of the switches 62' and 63'. 'Ihls closes one or both ofthe solenoid valves 64 and 65.

Assume for lpresent purposes that the roomette sections adjacent to car side 2 are cooled down the proper amount before the sections adjacent to car side |3 so that cooling thermostat 48A ceases calling for cooling, while ther ostat 49 continues to demand cooling. Under these conditions, blower fan 3| will circulate through the .conditioned air duct 21 air at a temperature corresponding to temperature conditions in the plenum,l/ianber, while the blower fan 3|' will pass air' over the evaporator 43, which is being A circuit breaker |9| is placed in the control circuit which functions when an over-load, due

to a short or the like, is` placed on the control circuit, and when this circuit breaker is opened a pilot light. |02 is cate trouble.

When the blower fan switch 56 is turned to placed in the circuit to indithe oi position, indicated in solid lines in Fig.

4, the blower fan ceases operating and the entire control circuit becomes dead except for the heat protection relay circuit which operates in1response to the heat protection thermostat 69, to prevent freezing of the water pip'es, etc., in the car.A When this thermostat calls for heating, the heat protection relay 68 becomes energized, closing the circuit to the floor heating system, thereby supplying heat to the floor heating coils.

cooled so asto pass air through conditioned air duct 28 at a temperature considerably below plenum chamber temperature conditions. Thus we have the situation where we are cooling the air along one side of the car only, thereby producing a uniform temperature throughout the car interior.

In the present disclosure, cooling thermostats 48` and 49 are made up of three thermostatic units each, each of which units is designed to function at a different critical temperature. Seasonal selector switch 58 may be adjusted to select any one of the three thermostatic units in each of the cooling thermostats 48 and 49, thereby affording a choice as to what-temperature the cooling thermostats 48 and 49 will function to operate the cooling pilot relay.

Since the compressor 1 is driven from the car axle 63 when the car is in motion, a speed conlimit the speed of operation of the compressor during high speed operation of the car. A speed control relay indicated at |05 controls the operation of this speed control, but, since it forms no part of the present invention, a detailed descriptionis believed unnecessary.

The relays 62 and 63 are connected in parallel 'so'that the ,speed control relay |05 is de-energized only when both of the cooling pilot relays become de-energized. Thus it is seen that, if either or both of the cooling pilot relays are energized so as to be 'calling for car cooling, the compressor 'I is operating.

It is thus seen that the air conditioning system forming thesubject matter of the present invention provides uniform temperature conditions dthroughout all the sections in the car body by providing means for cooling one portion of` the car when that portion-requires cooling at a time when another portion of the car doesnot require cooling.

The electric current source for energizing the control circuit as shown is a battery, but, ob-

viously, a generator may be employed if desired. The battery terminals are indicated by the letters B, R, and L, the B and R terminals being at all times in a position to supply current tothe circuit when the proper switches are closed, but the L circuit may be closed only when the master light switch, positioned on the electric control panels, is in a closed position. Thus when the car is in the yards and the master light switch is turned off, the L terminal of the battery is dead. A

Fuses |06 are placed in the various circuits for protection purposes.V

A manual switch |01 is provided in each of the heating relay circuits, and its function is to permit manual control of the magnetic heat valves in the 'event the valves fail to operate automatically.

What I claim is:

tioned air duct for each zone, an exhaust air duct foreach zone, heating means in each conditioned air duct, thermostatic control means in each conditioned air duct for controlling' the operation of its corresponding heating means, auxiliary heating means distributed throughout each zone, thermostatic control means in each exhaust air duct responsive to the mean temperature in its corresponding zone for controlling the operation of the auxiliary heating means, air circulating means for passing air through the conditioned air ducts, and means for discharging the exhaust air from the exhaust air ducts.

2. In a vehicle, an air conditioning system including a conditioned air d uct discharging on one side of the vehicle, a second conditioned air duct discharging on the other side of the vehicle, a pair of exhaust air ducts adapted to withdraw air from opposite sides of the vehicle and discharge it from the vehicle body, heating means in each conditioned air duct, thermostatic control means in each conditioned air duct for controlling the operation of its corresponding heating means, auxiliary heating me`ans in each side of the vehicle, thermostatic control means in each exhaust air duct for controlling the side of the vehicle, and means forpassing air through the conditioned and exhaust air ducts.

3. In a railway car having an aisle extending lengthwise along the center of the car, two zones each comprising a plurality of rooms on opposite sides of the aisle, air conditioning means comprising a separate air supply duct extending y along the aisle for each zone and having an outlet opening into each room thereof, separate heat exchange means in each supply duct ad- ,jacent to the inlet to said duct and anterior to the air therein, means discharging the last named portions to the exterior of the vehicle, and separate thermostatic means responsive to air in each exhaust duct posterior to the outlets from all of the rooms served by said duct controlling the heat exchange means' for all of said last named rooms, whereby each room of the vehicle is normally supplied with an unvarying quantity of airand the temperature of the air supplied to each zone is determined by the average temperature exhausted from the rooms in each supply duct adjacent to the inlet to said duct and anterior to the zones supplied by said duct, blower meansV for passing air through the ducts, said zones and ducts having openings to the aisle for recirculation of most of the air supplied to said zones, a separate air exhaust duct for each zone having an outlet from its corresponding zone for withdrawing a relatively small portion of the air therein, means discharging the last named portions to the exterior of the vehicle and separate thermostatic means responsive to air in each exhaust duct posterior to the outlet of the zone served by said duct controlling the heat exchange means for said zone.

5. In a vehicle, 'a plurality of rooms on opposite sides of a central aisle of said vehicle, an air conditioning system including a conditioned air duct discharging on o ne side of the vehicle into the rooms on the said side of the vehicle,

a second conditioned air duct discharging into vehicle in the .rooms thereof, thermostatic conl trol means in eachexhaust air duct for controlling the auxiliary heating means on the corresponding side of the vehicle. and means for passing air through the conditioned and exhaust auxiliary heating means on the corresponding FRANK L. MURPHY. 

